Logic App error using workflow parameters

I received the following error when deploying a Logic App via Powershell/ARM:
InvalidTemplate. Unable to process template language expressions in action ‘HTTP’ inputs at line ‘1’ and column ‘1420’: ‘The workflow parameter ‘ahakStorageConnectorName’ is not found.’.

At the top of the Logic App Json file, I defined the parameters. The parameter values were contained in a separate parameters.json file. I thought it would work when using a deploy statement in Powershell referencing both the json template file and the parameter file, like this:
$logicAppTemplate = $baseDir + ‘\ProcessAGP.json’
$logicAppParameter = $baseDir + ‘\ProcessAGP.parameters.json’
New-AzureRmResourceGroupDeployment -Name ‘DeployAGPTst’ -ResourceGroupName $resourcegroup -TemplateFile $logicAppTemplate -TemplateParameterFile $logicAppParameter

As I received an error I took a different approach. If you scroll down the json template file, you’ll notice there are an additional two parameter sections.
In the first parameter section I copied the parameter definitions from the top of the json template file. In the second parameter section I copied the parameter values from the parameters.json file.
This is apparantly the way, you can make parameters available to a Logic App.